Focus question

how would one compute the following problem? my book doesnt show examples liek this one

A focus of x^2/169 + y^2/25 = 1 is

-Maxwell

maxboy0801 said:

My book doesnt show examples like this one

Click to expand...

I'm having trouble believign that. You musn't be looking in the right place.

A focus of x^2/169 + y^2/25 = 1

Do you recognize an ellipse?
Major Axis length 13*2 = 26 - parallel to the x-axis ==> a = 13
Minor Axis length 5*2 = 10 - parallel to the y-axis ==> b = 5

These are things you should simply pull out of yoru hat when encountering such an expression.

c² = a² - b²

You really don't need more than that.